The protein encoded by this gene is a member of the intercellular adhesion molecule (ICAM) family. All ICAM proteins are type I transmembrane glycoproteins contain 2-9 immunoglobulin-like C2-type domains and bind to the leukocyte adhesion LFA-1 protein. This protein is expressed on the surface of telencephalic neurons and displays two types of adhesion activity homophilic binding between neurons and heterophilic binding between neurons and leukocytes. It may be a critical component in neuron-microglial cell interactions in the course of normal development or as part of neurodegenerative diseases. [provided by RefSeq Jul 2008]